Cyproconazole Translocation in Coconut Palm Tree Using Vegetative Endotherapy: Evaluation by LC-MS/MS and Mathematical Modeling

Abstract

Endotherapy is a potential eco-friendly alternative to conventional pesticide application techniques in coconut (Cocos nucifera Linn.) palms. Field trials applying cyproconazole by vegetative endotherapy using two different injection methods, pressurized and nonpressurized, were tested. Stem samples above the injection point were collected 2 to 45 days after application, and fruits were collected up to 45 to 120 days after application. Residue analyses on the coconut fruit and stem above the point of application of cyproconazole were performed on different days using modified QuEChERS (an acronym for “quick, easy, cheap, effective, rugged, and safe”) and LC-MS/MS MS (liquid chromatography–tandem mass spectrometry). For cyproconazole application in 2 m tall hybrid coconut palms, the residue analysis results revealed that the pressurized method achieves faster translocation and higher concentrations of cyproconazole in the upper part than the nonpressurized method, even when applying half the volume. After 120 days of application, both methods showed residue-free fruits, ensuring fruit quality. Based on these experimental results, mathematical models were developed to aid in interpreting translocation in the stem. The modeling was extrapolated for taller coconut palms, and a prediction was simulated for coconut leaf disease. The modeling was fitted to the stem translocation data, indicating that the pressurized method performs better in translocation efficiency.